In this paper, we explore possible conflict between morphological and molecular interpretations of phylogenetic relationships within the well-known peritrichous genus Zoothamnium. On the basis of morphological evidenc...In this paper, we explore possible conflict between morphological and molecular interpretations of phylogenetic relationships within the well-known peritrichous genus Zoothamnium. On the basis of morphological evidence, for a long time this genus has been believed to be a well-defined monophyletic taxon. Nonetheless, Zoothamnium exhibits higher genetic diversity than the gross morphology of its species. Here, we used all available genetic information for the small subunit of ribosomal RNA （SSU rRNA） and internal transcribed spacer region （ITS1-5.8S-ITS2） for this genus to reconstruct phylogenies for four datasets （SSU rRNA, ITS1, ITS2, and ITS1-5.8S-ITS2） and a combined dataset （SSU rRNA＋ITSI-5.8S- ITS2） using different phylogenetic methods and with consideration of the secondary structure of the genes. Confidence in phylogenetic tree selection was assessed with the approximately unbiased test. The molecular results showed both that Zoothamnium is more likely to be polyphyletic, and morphologically similar genera Zoothamnopsis and Myoschiston were always nested among Zoothamnium species. Accordingly, as with some other groups of ciliates, to understand more fully the correct phylogeny of Zoothamnium there remains a need for additional data from both morphological and molecular studies, covering additional Zoothamnium spp. and members of closely related genera （e.g. Zoothamnopsis, Myoschiston, and Epistylis）.展开更多
MicroRNAs (miRNAs) are a specialized class of small silencing RNAs that regulate gene expression in eukaryotes.In plants,miRNAs negatively regulate target mRNAs containing a highly complementary sequence by either mRN...MicroRNAs (miRNAs) are a specialized class of small silencing RNAs that regulate gene expression in eukaryotes.In plants,miRNAs negatively regulate target mRNAs containing a highly complementary sequence by either mRNA cleavage or translational repression.As a model plant to study fleshy fruit ripening,miRNA studies in tomato have made great progress recently.MiRNAs were predicted to be involved in nearly all biological processes in tomato,particularly development,differentiation,and biotic and abiotic stress responses.Surprisingly,several miRNAs were verified to be involved in tomato fruit ripening and senescence.Recent studies suggest that miRNAs are related to host-virus interactions,which raises the possibility that miRNAs can be used as diagnostic markers for response to virus infection in tomato plants.In this review,we summarize our current knowledge systematically and advance future directions for miRNA research in tomato.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.31071898,31111120437)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China+1 种基金the Key Laboratory of Mariculture(KLM),Ministry of Education,Ocean University of China,the Research Group Project(No.RGP-VPP-083)the King Saud University Deanship of Scientific Research
文摘In this paper, we explore possible conflict between morphological and molecular interpretations of phylogenetic relationships within the well-known peritrichous genus Zoothamnium. On the basis of morphological evidence, for a long time this genus has been believed to be a well-defined monophyletic taxon. Nonetheless, Zoothamnium exhibits higher genetic diversity than the gross morphology of its species. Here, we used all available genetic information for the small subunit of ribosomal RNA （SSU rRNA） and internal transcribed spacer region （ITS1-5.8S-ITS2） for this genus to reconstruct phylogenies for four datasets （SSU rRNA, ITS1, ITS2, and ITS1-5.8S-ITS2） and a combined dataset （SSU rRNA＋ITSI-5.8S- ITS2） using different phylogenetic methods and with consideration of the secondary structure of the genes. Confidence in phylogenetic tree selection was assessed with the approximately unbiased test. The molecular results showed both that Zoothamnium is more likely to be polyphyletic, and morphologically similar genera Zoothamnopsis and Myoschiston were always nested among Zoothamnium species. Accordingly, as with some other groups of ciliates, to understand more fully the correct phylogeny of Zoothamnium there remains a need for additional data from both morphological and molecular studies, covering additional Zoothamnium spp. and members of closely related genera （e.g. Zoothamnopsis, Myoschiston, and Epistylis）.
基金supported by the National Natural Science Foundation of China (Grant Nos. 30871741 and 30972037)
文摘MicroRNAs (miRNAs) are a specialized class of small silencing RNAs that regulate gene expression in eukaryotes.In plants,miRNAs negatively regulate target mRNAs containing a highly complementary sequence by either mRNA cleavage or translational repression.As a model plant to study fleshy fruit ripening,miRNA studies in tomato have made great progress recently.MiRNAs were predicted to be involved in nearly all biological processes in tomato,particularly development,differentiation,and biotic and abiotic stress responses.Surprisingly,several miRNAs were verified to be involved in tomato fruit ripening and senescence.Recent studies suggest that miRNAs are related to host-virus interactions,which raises the possibility that miRNAs can be used as diagnostic markers for response to virus infection in tomato plants.In this review,we summarize our current knowledge systematically and advance future directions for miRNA research in tomato.
